[PATCH] drm/bridge: analogix_dp: detect Sink PSR state after configuring the PSR

[Yakir Yang]

Make sure the request PSR state could effect in analogix_dp_send_psr_spd()
function, or printing the error Sink PSR state if we failed to effect
the request PSR setting.

Signed-off-by: Yakir Yang <ykk at rock-chips.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |  6 ++---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  4 ++--
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  | 26 ++++++++++++++++++++--
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index efac8ab..5a37de8 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -115,8 +115,7 @@ int analogix_dp_enable_psr(struct device *dev)
        psr_vsc.DB0 = 0;
        psr_vsc.DB1 = EDP_VSC_PSR_STATE_ACTIVE | EDP_VSC_PSR_CRC_VALUES_VALID;

-       analogix_dp_send_psr_spd(dp, &psr_vsc);
-       return 0;
+       return analogix_dp_send_psr_spd(dp, &psr_vsc);
 }
 EXPORT_SYMBOL_GPL(analogix_dp_enable_psr);

@@ -138,8 +137,7 @@ int analogix_dp_disable_psr(struct device *dev)
        psr_vsc.DB0 = 0;
        psr_vsc.DB1 = 0;

-       analogix_dp_send_psr_spd(dp, &psr_vsc);
-       return 0;
+       return analogix_dp_send_psr_spd(dp, &psr_vsc);
 }
 EXPORT_SYMBOL_GPL(analogix_dp_disable_psr);

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index 473b980..f617a9d 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -283,7 +283,7 @@ void analogix_dp_config_video_slave_mode(struct 
analogix_dp_device *dp);
 void analogix_dp_enable_scrambling(struct analogix_dp_device *dp);
 void analogix_dp_disable_scrambling(struct analogix_dp_device *dp);
 void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp);
-void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
-                             struct edp_vsc_psr *vsc);
+int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
+                            struct edp_vsc_psr *vsc);

 #endif /* _ANALOGIX_DP_CORE_H */
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 52c1b6b..505e9d8 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1328,9 +1328,11 @@ void analogix_dp_enable_psr_crc(struct 
analogix_dp_device *dp)
        writel(PSR_VID_CRC_ENABLE, dp->reg_base + ANALOGIX_DP_CRC_CON);
 }

-void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
-                             struct edp_vsc_psr *vsc)
+int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
+                            struct edp_vsc_psr *vsc)
 {
+       unsigned long timeout;
+       unsigned char sink;
        unsigned int val;

        /* don't send info frame */
@@ -1372,4 +1374,24 @@ void analogix_dp_send_psr_spd(struct analogix_dp_device 
*dp,
        val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
        val |= IF_EN;
        writel(val, dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
+
+       timeout = jiffies + msecs_to_jiffies(100);
+       while (1) {
+               analogix_dp_read_byte_from_dpcd(dp, DP_PSR_STATUS, &sink);
+
+               if (vsc->DB1 && sink == DP_PSR_SINK_ACTIVE_RFB)
+                       break;
+
+               if (!vsc->DB1 && sink == DP_PSR_SINK_INACTIVE)
+                       break;
+
+               if (time_after(jiffies, timeout)) {
+                       dev_warn(dp->dev, "Failed to effect PSR: %x", sink);
+                       return -EBUSY;
+               }
+
+               usleep_range(1000, 1500);
+       }
+
+       return 0;
 }
-- 
1.9.1